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25 //
26 //
27 //
28 // Hadronic Process: Nuclear De-excitations
29 // by V. Lara
30
31 #include <numeric>
32
33 #include "G4StatMFMicroCanonical.hh"
34 #include "G4PhysicalConstants.hh"
35 #include "G4SystemOfUnits.hh"
36 #include "G4HadronicException.hh"
37 #include "G4Pow.hh"
38
39 // constructor
40 G4StatMFMicroCanonical::G4StatMFMicroCanonical(G4Fragment const & theFragment)
41 {
42 // Perform class initialization
43 Initialize(theFragment);
44 }
45
46 // destructor
47 G4StatMFMicroCanonical::~G4StatMFMicroCanonical()
48 {
49 // garbage collection
50 if (!_ThePartitionManagerVector.empty()) {
51 std::for_each(_ThePartitionManagerVector.begin(),
52 _ThePartitionManagerVector.end(),
53 DeleteFragment());
54 }
55 }
56
57 void G4StatMFMicroCanonical::Initialize(const G4Fragment & theFragment)
58 {
59
60 std::vector<G4StatMFMicroManager*>::iterator it;
61
62 // Excitation Energy
63 G4double U = theFragment.GetExcitationEnergy();
64
65 G4int A = theFragment.GetA_asInt();
66 G4int Z = theFragment.GetZ_asInt();
67 G4double x = 1.0 - 2.0*Z/G4double(A);
68 G4Pow* g4calc = G4Pow::GetInstance();
69
70 // Configuration temperature
71 G4double TConfiguration = std::sqrt(8.0*U/G4double(A));
72
73 // Free internal energy at Temperature T = 0
74 __FreeInternalE0 = A*(
75 // Volume term (for T = 0)
76 -G4StatMFParameters::GetE0() +
77 // Symmetry term
78 G4StatMFParameters::GetGamma0()*x*x
79 ) +
80 // Surface term (for T = 0)
81 G4StatMFParameters::GetBeta0()*g4calc->Z23(A) +
82 // Coulomb term
83 elm_coupling*0.6*Z*Z/(G4StatMFParameters::Getr0()*g4calc->Z13(A));
84
85 // Statistical weight
86 G4double W = 0.0;
87
88 // Mean breakup multiplicity
89 __MeanMultiplicity = 0.0;
90
91 // Mean channel temperature
92 __MeanTemperature = 0.0;
93
94 // Mean channel entropy
95 __MeanEntropy = 0.0;
96
97 // Calculate entropy of compound nucleus
98 G4double SCompoundNucleus = CalcEntropyOfCompoundNucleus(theFragment,TConfiguration);
99
100 // Statistical weight of compound nucleus
101 _WCompoundNucleus = 1.0;
102
103 W += _WCompoundNucleus;
104
105 // Maximal fragment multiplicity allowed in direct simulation
106 G4int MaxMult = G4StatMFMicroCanonical::MaxAllowedMultiplicity;
107 if (A > 110) MaxMult -= 1;
108
109 for (G4int im = 2; im <= MaxMult; im++) {
110 G4StatMFMicroManager * aMicroManager =
111 new G4StatMFMicroManager(theFragment,im,__FreeInternalE0,SCompoundNucleus);
112 _ThePartitionManagerVector.push_back(aMicroManager);
113 }
114
115 // W is the total probability
116 W = std::accumulate(_ThePartitionManagerVector.begin(),
117 _ThePartitionManagerVector.end(),
118 W, [](const G4double& running_total,
119 G4StatMFMicroManager*& manager)
120 {
121 return running_total + manager->GetProbability();
122 } );
123
124 // Normalization of statistical weights
125 for (it = _ThePartitionManagerVector.begin(); it != _ThePartitionManagerVector.end(); ++it)
126 {
127 (*it)->Normalize(W);
128 }
129
130 _WCompoundNucleus /= W;
131
132 __MeanMultiplicity += 1.0 * _WCompoundNucleus;
133 __MeanTemperature += TConfiguration * _WCompoundNucleus;
134 __MeanEntropy += SCompoundNucleus * _WCompoundNucleus;
135
136 for (it = _ThePartitionManagerVector.begin(); it != _ThePartitionManagerVector.end(); ++it)
137 {
138 __MeanMultiplicity += (*it)->GetMeanMultiplicity();
139 __MeanTemperature += (*it)->GetMeanTemperature();
140 __MeanEntropy += (*it)->GetMeanEntropy();
141 }
142
143 return;
144 }
145
146 G4double G4StatMFMicroCanonical::CalcFreeInternalEnergy(const G4Fragment & theFragment,
147 G4double T)
148 {
149 G4int A = theFragment.GetA_asInt();
150 G4int Z = theFragment.GetZ_asInt();
151 G4double A13 = G4Pow::GetInstance()->Z13(A);
152
153 G4double InvLevelDensityPar = G4StatMFParameters::GetEpsilon0()
154 *(1.0 + 3.0/G4double(A-1));
155
156 G4double VolumeTerm = (-G4StatMFParameters::GetE0()+T*T/InvLevelDensityPar)*A;
157
158 G4double SymmetryTerm = G4StatMFParameters::GetGamma0()
159 *(A - 2*Z)*(A - 2*Z)/G4double(A);
160
161 G4double SurfaceTerm = (G4StatMFParameters::Beta(T)
162 - T*G4StatMFParameters::DBetaDT(T))*A13*A13;
163
164 G4double CoulombTerm = elm_coupling*0.6*Z*Z/(G4StatMFParameters::Getr0()*A13);
165
166 return VolumeTerm + SymmetryTerm + SurfaceTerm + CoulombTerm;
167 }
168
169 G4double
170 G4StatMFMicroCanonical::CalcEntropyOfCompoundNucleus(const G4Fragment & theFragment,
171 G4double & TConf)
172 // Calculates Temperature and Entropy of compound nucleus
173 {
174 G4int A = theFragment.GetA_asInt();
175 G4double U = theFragment.GetExcitationEnergy();
176 G4double A13 = G4Pow::GetInstance()->Z13(A);
177
178 G4double Ta = std::max(std::sqrt(U/(0.125*A)),0.0012*MeV);
179 G4double Tb = Ta;
180
181 G4double ECompoundNucleus = CalcFreeInternalEnergy(theFragment,Ta);
182 G4double Da = (U+__FreeInternalE0-ECompoundNucleus)/U;
183 G4double Db = 0.0;
184
185 G4double InvLevelDensity = CalcInvLevelDensity(A);
186
187 // bracketing the solution
188 if (Da == 0.0) {
189 TConf = Ta;
190 return 2*Ta*A/InvLevelDensity - G4StatMFParameters::DBetaDT(Ta)*A13*A13;
191 } else if (Da < 0.0) {
192 do {
193 Tb -= 0.5*Tb;
194 ECompoundNucleus = CalcFreeInternalEnergy(theFragment,Tb);
195 Db = (U+__FreeInternalE0-ECompoundNucleus)/U;
196 } while (Db < 0.0);
197 } else {
198 do {
199 Tb += 0.5*Tb;
200 ECompoundNucleus = CalcFreeInternalEnergy(theFragment,Tb);
201 Db = (U+__FreeInternalE0-ECompoundNucleus)/U;
202 } while (Db > 0.0);
203 }
204
205 G4double eps = 1.0e-14 * std::abs(Tb-Ta);
206
207 for (G4int i = 0; i < 1000; i++) {
208 G4double Tc = (Ta+Tb)*0.5;
209 if (std::abs(Ta-Tb) <= eps) {
210 TConf = Tc;
211 return 2*Tc*A/InvLevelDensity - G4StatMFParameters::DBetaDT(Tc)*A13*A13;
212 }
213 ECompoundNucleus = CalcFreeInternalEnergy(theFragment,Tc);
214 G4double Dc = (U+__FreeInternalE0-ECompoundNucleus)/U;
215
216 if (Dc == 0.0) {
217 TConf = Tc;
218 return 2*Tc*A/InvLevelDensity - G4StatMFParameters::DBetaDT(Tc)*A13*A13;
219 }
220
221 if (Da*Dc < 0.0) {
222 Tb = Tc;
223 Db = Dc;
224 } else {
225 Ta = Tc;
226 Da = Dc;
227 }
228 }
229
230 G4cout <<
231 "G4StatMFMicrocanoncal::CalcEntropyOfCompoundNucleus: I can't calculate the temperature"
232 << G4endl;
233
234 return 0.0;
235 }
236
237 G4StatMFChannel * G4StatMFMicroCanonical::ChooseAandZ(const G4Fragment & theFragment)
238 // Choice of fragment atomic numbers and charges
239 {
240 // We choose a multiplicity (1,2,3,...) and then a channel
241 G4double RandNumber = G4UniformRand();
242
243 if (RandNumber < _WCompoundNucleus) {
244
245 G4StatMFChannel * aChannel = new G4StatMFChannel;
246 aChannel->CreateFragment(theFragment.GetA_asInt(),theFragment.GetZ_asInt());
247 return aChannel;
248
249 } else {
250
251 G4double AccumWeight = _WCompoundNucleus;
252 std::vector<G4StatMFMicroManager*>::iterator it;
253 for (it = _ThePartitionManagerVector.begin(); it != _ThePartitionManagerVector.end(); ++it) {
254 AccumWeight += (*it)->GetProbability();
255 if (RandNumber < AccumWeight) {
256 return (*it)->ChooseChannel(theFragment.GetA_asInt(),theFragment.GetZ_asInt(),__MeanTemperature);
257 }
258 }
259 throw G4HadronicException(__FILE__, __LINE__, "G4StatMFMicroCanonical::ChooseAandZ: wrong normalization!");
260 }
261
262 return 0;
263 }
264
265 G4double G4StatMFMicroCanonical::CalcInvLevelDensity(G4int anA)
266 {
267 G4double res = 0.0;
268 if (anA > 1) {
269 res = G4StatMFParameters::GetEpsilon0()*(1.0+3.0/(anA - 1.0));
270 }
271 return res;
272 }
273